Enhanced Fe-TiO₂ Solar Photocatalysts on Porous Platforms for Water Purification

In this study, polyethylene glycol-modified titanium dioxide (PEG-modified TiO₂) nanopowders were prepared using a fast solvothermal method under microwave irradiation, and without any further calcination processes. These nanopowders were further impregnated on porous polymeric platforms by drop-casting. The effect of adding iron with different molar ratios (1, 2, and 5%) of iron precursor was investigated. The characterization of the produced materials was carried out by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. Optical characterization of all the materials was also carried out. SEM showed that pure TiO₂ and Fe-TiO₂ nanostructures presented similar nanosized and spherical particles, which uniformly covered the substrates. From XRD, pure TiO₂ anatase was obtained for all nanopowders produced, which was further confirmed by Raman spectroscopy on the impregnated substrates. XPS and UV-VIS absorption spectroscopy emission spectra revealed that the presence of Fe ions on the Fe-TiO₂ nanostructures led to the introduction of new intermediate energy levels, as well as defects that contributed to an enhancement in the photocatalytic performance. The photocatalytic results under solar radiation demonstrated increased photocatalytic activity in the presence of the 5% Fe-TiO₂ nanostructures (Rhodamine B degradation of 85% after 3.5 h, compared to 74% with pure TiO₂ for the same exposure time). The photodegradation rate of RhB dye with the Fe-TiO₂ substrate was 1.5-times faster than pure TiO₂. Reusability tests were also performed. The approach developed in this work originated novel functionalized photocatalytic platforms, which were revealed to be promising for the removal of organic dyes from wastewater.